package org.zb.security.captcha;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

public class ImageCaptcha {
	
		public static String CaptchaCodeName = "captchaCode";
		
		public static String CaptchaTimeName = "captchaTime";

	    private static char mapTable[] = {
	            '0', '1', '2', '3', '4', '5',
	            '6', '7', '8', '9', '0', '1',
	            '2', '3', '4', '5', '6', '7',
	            '8', '9'};

	    public static Map<String, Object> getImageCode(int width, int height, OutputStream os) {
	        Map<String,Object> returnMap = new HashMap<String, Object>();
	        if (width <= 0) width = 60;
	        if (height <= 0) height = 20;
	        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
	        // 获取图形上下文
	        Graphics g = image.getGraphics();
	        //生成随机类
	        Random random = new Random();
	        // 设定背景色
	        g.setColor(getRandColor(200, 250));
	        g.fillRect(0, 0, width, height);
	        //设定字体
	        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
	        // 随机产生168条干扰线，使图象中的认证码不易被其它程序探测到
	        g.setColor(getRandColor(80, 160));
	        for (int i = 0; i < 32; i++) {
	            int x = random.nextInt(width);
	            int y = random.nextInt(height);
	            int xl = random.nextInt(12);
	            int yl = random.nextInt(12);
	            g.drawLine(x, y, x + xl, y + yl);
	        }
	        //取随机产生的码
	        String strEnsure = "";
	        //4代表4位验证码,如果要生成更多位的认证码,则加大数值
	        for (int i = 0; i < 4; ++i) {
	            strEnsure += mapTable[(int) (mapTable.length * Math.random())];
	            // 将认证码显示到图象中
	            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
	            //直接生成
	            String str = strEnsure.substring(i, i + 1);
	            g.drawString(str, 13 * i + 6, 16);
	        }

	        // 释放图形上下文
	        g.dispose();
	        returnMap.put("image",image);
	        returnMap.put(CaptchaCodeName,strEnsure);
	        return returnMap;
	    }

	    //给定范围获得随机颜色
	    static Color getRandColor(int fc, int bc) {
	        Random random = new Random();
	        if (fc > 255) fc = 255;
	        if (bc > 255) bc = 255;
	        int r = fc + random.nextInt(bc - fc);
	        int g = fc + random.nextInt(bc - fc);
	        int b = fc + random.nextInt(bc - fc);
	        return new Color(r, g, b);
	    }
	}
